1. Field of the Invention
The present invention relates to a multilayer ceramic capacitor and a mounting circuit board therefor.
2. Description of the Related Art
A multilayer ceramic capacitor (MLCC) one of multilayer chip electronic components, may be used in various electronic devices, due to advantages thereof such as a small size, high capacitance, easiness of mounting, and the like.
For example, a multilayer ceramic capacitor may be used as a chip type condenser mounted on circuit boards of various electronic products including display devices such as liquid crystal displays (LCDs), plasma display panels (PDPs), and the like, computers, personal digital assistants (PDAs), cellular phones, and the like, to charge or discharge electricity.
The multilayer ceramic capacitor may have a structure in which a plurality of dielectric layers and internal electrodes having opposite polarities and interposed between the dielectric layers are alternately laminated.
In this case, since the dielectric layers have piezoelectric properties, when direct current (DC) voltage or alternating current (AC) voltage is applied to the multilayer ceramic capacitor, a piezoelectric phenomenon may be generated between the internal electrodes, such that a volume of a ceramic body is expanded and contracted according to frequency, thereby generating periodic vibrations.
The vibrations may be transmitted to a circuit board through external electrodes of the multilayer ceramic capacitor and a solder connecting the external electrodes to the circuit board, such that the entire circuit board may become an acoustically reflective surface to generate a vibration sound as noise.
The vibration sound may correspond to an audible frequency range of 20 to 20,000 Hz making listeners unpleasant. The vibration sound, potentially providing unpleasant feeling to listeners, is known as acoustic noise.
Recently, since acoustic noise generated in the multilayer ceramic capacitor as described above may be evident due to noise decrease in components of electronic devices, research into a technology for effectively decreasing the acoustic noise generated in the multilayer ceramic capacitor has been required.
In order to decrease the acoustic noise, a method of mounting the multilayer ceramic capacitor on the circuit board so as to be spaced apart from each other by a predetermined distance using a metal frame has been disclosed.
However, in order to decrease the acoustic noise to a predetermined level by using the metal frame, a distance between the metal frame and the circuit board should be increased to be greater than a predetermined standard distance.
In addition, since the above-described distance increase between the metal frame and the circuit board results in an increase in a height of a product in which the multilayer ceramic capacitor is mounted, it may be difficult to use the metal frame in a set having a height limitation.
Patent Document 1 discloses a multilayer ceramic capacitor capable of improving equivalent series resistance (ESR) and suppressing occurrence of connection defects.